如何在 Swift 3.0 中使用 Storyboard 在控制器之间传递数据？

Question

如何在 swift 3.0 中使用 UIStoryboard 在控制器之间传递数据？

我创建了 login (LoginViewController) 和 main (ViewController) 应用程序保持活动的页面如果用户没有注销。

到目前为止它有效。

我有这些 JSON 值 "login" 需要从 LoginViewController[=46 传递=] 变成 ViewController

有些人建议使用 执行和准备 segue。

有效，但只有从登录ViewController发送时才能显示该值。

ViewController 在页面 ViewController 处于活动状态时（当我 rebuild/clean 应用程序时）没有保存数据。

我的目标是在页面处于活动状态时将 "login" 数据保留在 ViewController 中，并在页面注销时清除 "login" 数据。

LoginViewController.swift

import UIKit class LoginViewController: UIViewController { @IBOutlet var _loginLbl: UITextField! @IBOutlet var _pwLbl: UITextField! @IBOutlet var login_button: UIButton! @IBOutlet var outputLbl: UILabel! var login: String! var pw: String! override func viewDidLoad() {super.viewDidLoad()} @IBAction func loginData(_ sender: Any) { login = _loginLbl.text pw = _pwLbl.text let url = URL(string: "http://localhost/login.php") let session = URLSession.shared let request = NSMutableURLRequest(url: url! as URL) request.httpMethod = "POST" let LoginDataToPost = "login=\(login!)&pw=\(pw!)" request.httpBody = LoginDataToPost.data(using: String.Encoding.utf8) let task = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) in if error != nil { return } else { do { if let json = try JSONSerialization.jsonObject(with: data!) as? [String: String] { DispatchQueue.main.async { let message = Int(json["message"]!) let login = json["login"] if(message == 1) { UserDefaults.standard.set(true, forKey: "isUserLoggedIn") UserDefaults.standard.synchronize(); self.dismiss(animated: true, completion: nil) let myViewController:ViewController = self.storyboard!.instantiateViewController(withIdentifier: "ViewController") as! ViewController let appDelegate = UIApplication.shared.delegate as! AppDelegate appDelegate.window?.rootViewController = myViewController appDelegate.window?.makeKeyAndVisible() self.outputLbl.text = login; return } else { } } } else { } } catch let jsonParse {} } }) task.resume() } } }

ViewController.swift

import UIKit class ViewController: UIViewController { @IBOutlet var loginLbl: UILabel! var login: String! override func viewDidLoad() { super.viewDidLoad() let preferences = UserDefaults.standard if(preferences.object(forKey: "isUserLoggedIn") != nil){ loginLbl.text = login } else { } } override func viewDidAppear(_ animated: Bool) { let isUserLoggedIn = UserDefaults.standard.bool(forKey: "isUserLoggedIn") if(!isUserLoggedIn){ self.performSegue(withIdentifier: "loginview", sender: self) } } @IBAction func logoutData(_ sender: Any) { UserDefaults.standard.set(false, forKey: "isUserLoggedIn"); UserDefaults.standard.synchronize(); let loginViewController = self.storyboard!.instantiateViewController(withIdentifier: "loginview") as! LoginViewController let appDelegate = UIApplication.shared.delegate as! AppDelegate appDelegate.window?.rootViewController = loginViewController appDelegate.window?.makeKeyAndVisible() } }

有什么想法吗？

谢谢。

Answer 1

您可以将值存储在 LoginViewController 的 NSUserDefaults 中。如下所示：

UserDefaults.standard.set(login, forKey: "loginJSONValue")

然后像这样获取 ViewController 中的值（我假设该值是 String）：

textField1.text = UserDefaults.standard.object(forKey: "loginJSONValue") as? String

LoginViewController.swift

import UIKit
class LoginViewController: UIViewController {

    @IBOutlet var _loginLbl: UITextField!
    @IBOutlet var _pwLbl: UITextField!
    @IBOutlet var login_button: UIButton!

    @IBOutlet var outputLbl: UILabel!

    var login: String!
    var pw: String!

    override func viewDidLoad() {super.viewDidLoad()}

    @IBAction func loginData(_ sender: Any) {
        login = _loginLbl.text
        pw    = _pwLbl.text

            let url = URL(string: "http://localhost/login.php")
            let session = URLSession.shared

            let request = NSMutableURLRequest(url: url! as URL)
            request.httpMethod = "POST"

            let LoginDataToPost = "login=\(login!)&pw=\(pw!)"
            request.httpBody = LoginDataToPost.data(using: String.Encoding.utf8)

            let task = session.dataTask(with: request as URLRequest, completionHandler: {
                (data, response, error) in
                if error != nil {
                    return
                }
                else {
                    do {
                        if let json = try JSONSerialization.jsonObject(with: data!) as? [String: String]
                        {
                            DispatchQueue.main.async
                            {
                                let message = Int(json["message"]!)
                                let login   = json["login"]

                                if(message == 1) {
                                    UserDefaults.standard.set(true, forKey: "isUserLoggedIn")
                                    UserDefaults.standard.set(login, forKey: "loginJSONValue")
                                    UserDefaults.standard.synchronize();
                                    self.dismiss(animated: true, completion: nil)

                                    let myViewController:ViewController = self.storyboard!.instantiateViewController(withIdentifier: "ViewController") as! ViewController
                                    let appDelegate = UIApplication.shared.delegate as! AppDelegate
                                    appDelegate.window?.rootViewController = myViewController
                                    appDelegate.window?.makeKeyAndVisible()

                                    self.outputLbl.text = login;

                                    return
                                }
                                else { }
                            }  
                        }  
                        else { }
                    } catch let jsonParse {}
                }
            })
            task.resume()
        }
    }
}

ViewController.swift

import UIKit
class ViewController: UIViewController {
    @IBOutlet var loginLbl: UILabel!
    var login: String!
    override func viewDidLoad() {
        super.viewDidLoad()
    let preferences = UserDefaults.standard

         if(preferences.object(forKey: "isUserLoggedIn") != nil){

// let isUserLoggedIn = UserDefaults.standard.bool(forKey: "isUserLoggedIn")
            let isUserLoggedIn = UserDefaults.standard.object(forKey: "isUserLoggedIn") as Bool
    // your login data is below. do what you want to do
                login = UserDefaults.standard.object(forKey: "loginJSONValue") as String
                if(!isUserLoggedIn){
                    self.performSegue(withIdentifier: "loginview", sender: self)
                }
            loginLbl.text = login
         }
         else {

         }
    }
    override func viewDidAppear(_ animated: Bool) {

        }

        @IBAction func logoutData(_ sender: Any) {
            UserDefaults.standard.set(false, forKey: "isUserLoggedIn");
// After logging out, you can set empty to login data.
UserDefaults.standard.set("", forKey: "loginJSONValue");
            UserDefaults.standard.synchronize();
            let loginViewController = self.storyboard!.instantiateViewController(withIdentifier: "loginview") as! LoginViewController
            let appDelegate = UIApplication.shared.delegate as! AppDelegate
            appDelegate.window?.rootViewController = loginViewController
            appDelegate.window?.makeKeyAndVisible()
        }

    }

Answer 2

您需要重新调用登录服务，并在应用重启时传递数据。或者您可以将数据存储在 UserDefault 中并重新使用它。

UserDefaults.standard.set(login, forKey: "loginResponse")

您可以将数据从一个控制器传递到另一个控制器，如下所示：

  let myViewController:ViewController = self.storyboard!.instantiateViewController(withIdentifier: "ViewController") as! ViewController
var loginResponse = UserDefaults.standard.get(forKey:"loginResponse")
myViewController.your_object = loginResponse

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